Studies Show Lead Linked to Violent Crime Trends

Studies examining lead exposure show that higher childhood blood lead levels are consistently associated with higher adult arrest rates for violent crimes. This evidence points to gasoline lead as a convincing explanation for violent crime rates in the United States over the past 50 years.

Leaded gasoline consumption rose steadily from the early 1940s through the early 1970s and then fell as unleaded gasoline began to replace leaded gas. Crime rates follow the same pattern, about 20 years later: violent crime rose dramatically in the 1960s through the 1980s and then fell steadily starting in the early 1990s.

New neurological research demonstrates that lead's effects are very damaging at far lower levels than previously thought. Childhood lead exposure at nearly any level can seriously and permanently reduce IQ. Researchers have now shown that lead exposure impairs specific parts of the brain responsible for executive functions and it impairs the communication channels between these parts of the brain. And the neurological impact is greater among boys than girls.

Lead exposure is ongoing, even though unleaded has now replaced leaded gasoline, because lead spewed into the air from car exhaust has settled permanently into the soil, where it is seasonally kicked back into the air and tracked into homes as dust. Lead paint dust generated from opening and closing old windows is also a major source of lead exposure.

Experts suggest that lead abatement efforts directed at replacing lead-painted windows and soil clean-up in urban neighborhoods where leaded gasoline consumption was most concentrated would cost about $20 billion per year and save $210 billion annually from increases in IQ and reductions in violent crime.